#define _CRT_SECURE_NO_WARNINGS 1
#include <stdio.h>
#include <string.h>

int main() {
    char ch[1001] = { 0 };
    int i = 0;
    char c;

    while ((c = getchar()) != '\n') {
        ch[i++] = c;
    }
    int len = strlen(ch);

    for (int j = 0; j < len; j++) {
        for (int k = j + 1; k < len; k++) {
            if (ch[j] > ch[k]) {
                char temp = ch[j];
                ch[j] = ch[k];
                ch[k] = temp;
            }
        }
    }

    for (int i = 0; i < len; i++) {
        printf("%c", ch[i]);
    }

    return 0;
}